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SubTerra, Inc. Peabody Twentymile Coal LLC 09/27/2014 <br />Foidel Creek Mine <br />Permit Revision for Longwall Mining in the Wolf Creek Seam - Subsidence Evaluation <br />2. Structures on the Archer- Hayden line are predicted to subside by just over 3 -feet. <br />3. Structures on the Craig - Hayden - Steamboat line are predicted to subside by just over 2 -feet <br />4. Maximum daily subsidence is predicted to be less than 6- inches per day. <br />5. The duration of subsidence effects at each structure is expected to be between 25 and 35- <br />days. <br />6. In the case of the Archer- Hayden and Craig- Hayden - Steamboat lines, the length of the <br />traveling subsidence profile means that each structure will react independently which should <br />for the most part eliminate the potential for complex interactions. <br />7. Subsidence, tilt and strain magnitude at each Archer - Hayden and Craig- Hayden - Steamboat <br />structure are predicted to be lower than previously experienced by WAPA's line that crossed <br />the Eastern Mining District and by these two lines when they were previously undermined by <br />19 -Right in the Northern Mining District. <br />7.4. Water Wells <br />The evaluation presented in Section 6 predicts impacts to wells completed in the Wolf Creek Seam <br />and its immediate overburden. Minor impacts may also occur in shallow overburden wells but are <br />likely to be minor with recovery within one year after undermining. <br />7.5. Monitoring Reauirements <br />As noted in the introduction, Twentymile Coal Company has collected and submitted a large amount <br />of subsidence data from monitoring coal extraction in the Wadge Seam. They have also monitored <br />subsidence of the Power Lines, Fish and Foidel Creek and the Energy Spur railroad track during <br />sequential undermining. We recommend that monitoring both ground subsidence and structure <br />response continue focusing on verifying the predictions made herein. <br />Additional monitoring requirements associated with each of the evaluated structures and natural <br />features are presented above in Sections 3 through 6. <br />19 PN: 2013 -26 <br />